Experimental Loop HF Antenna

Picture 3 Reading of the MFJ- 993B on 20- meter Band

However, artificial ground, it was variable inductor with variable capacitor and thick wire in several meter length connected in serial, cancelled the biting. I decided find the impedance of the antenna at the antenna tuner. The tuner can shows value of the capacitor and inductor that is used for matching of the antenna. In the tuner it is used simple L- circuit, so it is possible to find impedance of the antenna based on the value of the L and C in matching circuit. Picture 4 shows value of the matching L- circuit on the 10- meter band. Table 1 shows antenna impedance on the HF bands calculated on the base of the values.

Antenna has very low active resistance on the 20- meter bands. I found that connection of the artificial ground increase the antenna input impedance, so it is improve the antenna efficiency.

However it does inconvenience- you need tune the artificial ground on the each band. Table 2 shows antenna impedance on the HF bands with artificial ground.

Antenna was tested in transmitting mode. Antenna works well on the 20- 10 meter Bands. As well it works satisfactory on the 40 and 30 meters. On the 80 meter Band the antenna works poor however I could be on the Air as on receiving and sometimes on transmitting chat with local hams. My opinion is that the antenna works and I will install it on my balcony.

73! de UA5AA

Table 1 Antenna Impedance on the HF Bands

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